Zoom lens and imaging apparatus

ABSTRACT

A zoom lens consists of, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, one or two middle lens groups including a mp lens group having a positive refractive power, and a rearmost lens group disposed at the most image side position of the entire system and having a positive refractive power, wherein magnification change is effected by changing all distances between the adjacent lens groups, and focusing from an object at infinity to a closest object is effected by moving only the entire mp lens group or only a part of lens groups forming the mp lens group along the optical axis, the lens group moved during focusing includes a positive lens and a negative lens and has a positive refractive power as a whole, and given condition expressions are satisfied.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 to JapanesePatent Application No. 2014-174106, filed on Aug. 28, 2014. The aboveapplication is hereby expressly incorporated by reference, in itsentirety, into the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a zoom lens which is suitable for usewith, in particular, digital cameras, lens-replaceable digital cameras,etc., and an imaging apparatus provided with the zoom lens.

2. Description of the Related Art

So-called constant aperture zoom lenses having a zoom ratio of around2.5 to 3.0, and a constant maximum aperture of around F2.8 or F4 acrossthe entire zoom range are known.

Such a zoom lens has a four-group or five-group configuration including,for example, in order from the object side, a first lens group which hasa positive refractive power and is fixed during magnification change, asecond lens group which has a negative refractive power and has a strongmagnification change effect, about one or two magnification changegroups which are provided in addition to the second lens group andinclude a lens group having a positive refractive power, and a rearmostlens group which is fixed during magnification change.

As a zoom lens having the above-described configuration, those disclosedin Japanese Unexamined Patent Publication Nos. 2011-099964, 2013-174758,2013-007878, 2012-027217, and 2011-158599 (hereinafter, Patent Documents1 to 5, respectively) are known.

SUMMARY OF THE INVENTION

In Patent Document 1, a part of lens groups forming the first lens groupis used to effect focusing, where the part of lens groups to effectfocusing has a large lens diameter, and a very large load is applied tothe focusing driving system.

In Patent Documents 2 to 5, the third lens group is used to effectfocusing, and size reduction and weight reduction of the focusing lensgroup are achieved. However, the maximum aperture is F4.1 in PatentDocuments 2 and 3, and thus Patent Documents 2 and 3 do not achieve ahigh aperture ratio. Patent Document 4 achieves a maximum aperture ofF2.9; however, the refractive power of the focusing lens group is weak,and the amount of movement of the focusing lens group is large. InPatent Document 5, contrary to Patent Document 4, the refractive powerof the focusing lens group is strong, and it is difficult to suppressvariation of aberrations during focusing.

In view of the above-described circumstances, the present invention isdirected to providing a zoom lens having a high aperture ratio and highoptical performance, wherein the focusing lens group is compact andlight weight, and the amount of movement of the focusing lens group issmall, as well as an imaging apparatus provided with the zoom lens.

A zoom lens of the invention consists of four or five lens groups as awhole, which consist of, in order from the object side, a first lensgroup having a positive refractive power, a second lens group having anegative refractive power, one or two middle lens groups including a mplens group having a positive refractive power, and a rearmost lens groupdisposed at the most image side position of the entire system and havinga positive refractive power,

wherein magnification change is effected by changing all distancesbetween the adjacent lens groups,

focusing from an object at infinity to a closest object is effected bymoving only the entire mp lens group or only a part of lens groupsforming the mp lens group along the optical axis,

the lens group moved during focusing includes at least one positive lensand at least one negative lens and has a positive refractive power as awhole, and

the condition expressions (1) and (2) below are satisfied:1.67<f1/fGf<2.70  (1), and1.15<f1/fGr<1.85  (2),where f1 is a focal length of the first lens group, fGf is a focallength of the lens group moved during focusing, and fGr is a focallength of the rearmost lens group.

It should be noted that the mp lens group is not a part of a lens group(a sub-lens group) and is one independent lens group. The “independentlens group” herein means such a lens group that the distance between thelens group and the adjacent lens group is changed during magnificationchange. In the case where the middle lens group consists of two lensgroups, and both the two lens groups have a positive refractive power,the mp lens group may be either of the lens groups.

In the zoom lens of the invention, it is preferred that the conditionexpression (1-1) and/or (2-1) below be satisfied:1.72<f1/fGf<2.60  (1-1)1.20<f1/fGr<1.75  (2-1).

It is preferred that the first lens group be fixed relative to the imageplane during magnification change.

It is preferred that the rearmost lens group be fixed relative to theimage plane during magnification change.

It is preferred that the lens group moved during focusing consist of twopositive lenses and one negative lens.

It is preferred that focusing from an object at infinity to a closestobject be effected by moving only the entire mp lens group along theoptical axis.

It is preferred that the condition expression (3) below be satisfied. Itis more preferred that the condition expression (3-1) below besatisfied.1.20<ft/f1<2.20  (3),1.23<ft/f1<2.00  (3-1),where ft is a focal length of the entire system when the lens is focusedon an object at infinity at the telephoto end, and f1 is a focal lengthof the first lens group.

It is preferred that the condition expression (4) below be satisfied. Itis more preferred that the condition expression (4-1) below besatisfied.5.30<ft/|f2|<8.80  (4),5.50<ft/|f2|<8.60  (4-1),where ft is a focal length of the entire system when the lens is focusedon an object at infinity at the telephoto end, and f2 is a focal lengthof the second lens group.

It is preferred that the condition expression (5) below be satisfied. Itis more preferred that the condition expression (5-1), (5-2), or (5-3)below be satisfied.57<νdGmp  (5),57<νdGmp<85  (5-1),59<νdGmp  (5-2),59<νdGmp<85  (5-3),where νdGmp is the largest Abbe number of the at least one positive lensin the lens group moved during focusing.

It is preferred that the first lens group consist of, in order from theobject side, a negative lens, a positive lens, a positive lens, and apositive lens.

It is preferred that the second lens group include two positive lensesand two negative lenses.

It is preferred that the zoom lens consist of four lens groups whichconsist of, in order from the object side, the first lens group, thesecond lens group, the mp lens group, and the rearmost lens group.

It is preferred that a stop be disposed at the most object-side positionof the rearmost lens group.

An imaging apparatus of the invention comprises the above-described zoomlens of the invention.

It should be noted that the expression “consisting/consist of” as usedherein means that the zoom lens may include, besides the elementsrecited above: lenses substantially without any power; optical elementsother than lenses, such as a stop, a mask, a cover glass, and filters;and mechanical components, such as a lens flange, a lens barrel, animage sensor, an image stabilization mechanism, etc.

The Abbe number is with respect to the d-line (the wavelength of 587.6nm).

The sign (positive or negative) with respect to the surface shape andthe refractive power of any lens including an aspheric surface are aboutthe paraxial region.

The zoom lens of the invention consists of four or five lens groups as awhole, which consist of, in order from the object side, a first lensgroup having a positive refractive power, a second lens group having anegative refractive power, one or two middle lens groups including a mplens group having a positive refractive power, and a rearmost lens groupdisposed at the most image side position of the entire system and havinga positive refractive power, wherein magnification change is effected bychanging all distances between the adjacent lens groups, focusing froman object at infinity to a closest object is effected by moving only theentire mp lens group or only a part of lens groups forming the mp lensgroup along the optical axis, the lens group moved during focusingincludes a positive lens and a negative lens and has a positiverefractive power as a whole, and the condition expressions (1) and (2)below are satisfied:1.67<f1/fGf<2.70  (1), and1.15<f1/fGr<1.85  (2).This configuration allows achieving a zoom lens having high apertureratio and having high optical performance, wherein the focusing lensgroup is compact and light weight and the amount of movement of thefocusing lens group is small.

The imaging apparatus of the invention, which is provided with the zoomlens of the invention, is compact and light weight, and allows obtaininghigh quality images.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view illustrating the lens configuration of a zoomlens according to one embodiment of the present invention (a zoom lensof Example 1),

FIG. 2 is a sectional view illustrating the lens configuration of a zoomlens of Example 2 of the invention,

FIG. 3 is a sectional view illustrating the lens configuration of a zoomlens of Example 3 of the invention,

FIG. 4 is a sectional view illustrating the lens configuration of a zoomlens of Example 4 of the invention,

FIG. 5 is a sectional view illustrating the lens configuration of a zoomlens of Example 5 of the invention,

FIG. 6 is a sectional view illustrating the lens configuration of a zoomlens of Example 6 of the invention,

FIG. 7 is a sectional view illustrating the lens configuration of a zoomlens of Example 7 of the invention,

FIG. 8 is a sectional view illustrating the lens configuration of a zoomlens of Example 8 of the invention,

FIG. 9 is a sectional view illustrating the lens configuration of a zoomlens of Example 9 of the invention,

FIG. 10 is a sectional view illustrating the lens configuration of azoom lens of Example 10 of the invention,

FIG. 11 is a sectional view illustrating the lens configuration of azoom lens of Example 11 of the invention,

FIG. 12 shows aberration diagrams of the zoom lens of Example 1 of theinvention,

FIG. 13 shows aberration diagrams of the zoom lens of Example 2 of theinvention,

FIG. 14 shows aberration diagrams of the zoom lens of Example 3 of theinvention,

FIG. 15 shows aberration diagrams of the zoom lens of Example 4 of theinvention,

FIG. 16 shows aberration diagrams of the zoom lens of Example 5 of theinvention,

FIG. 17 shows aberration diagrams of the zoom lens of Example 6 of theinvention,

FIG. 18 shows aberration diagrams of the zoom lens of Example 7 of theinvention,

FIG. 19 shows aberration diagrams of the zoom lens of Example 8 of theinvention,

FIG. 20 shows aberration diagrams of the zoom lens of Example 9 of theinvention,

FIG. 21 shows aberration diagrams of the zoom lens of Example 10 of theinvention,

FIG. 22 shows aberration diagrams of the zoom lens of Example 11 of theinvention,

FIG. 23 shows lateral aberration diagrams of the zoom lens of Example 1of the invention,

FIG. 24 shows lateral aberration diagrams of the zoom lens of Example 2of the invention,

FIG. 25 shows lateral aberration diagrams of the zoom lens of Example 3of the invention,

FIG. 26 shows lateral aberration diagrams of the zoom lens of Example 4of the invention,

FIG. 27 shows lateral aberration diagrams of the zoom lens of Example 5of the invention,

FIG. 28 shows lateral aberration diagrams of the zoom lens of Example 6of the invention,

FIG. 29 shows lateral aberration diagrams of the zoom lens of Example 7of the invention,

FIG. 30 shows lateral aberration diagrams of the zoom lens of Example 8of the invention,

FIG. 31 shows lateral aberration diagrams of the zoom lens of Example 9of the invention,

FIG. 32 shows lateral aberration diagrams of the zoom lens of Example 10of the invention,

FIG. 33 shows lateral aberration diagrams of the zoom lens of Example 11of the invention,

FIG. 34 is a perspective view showing the front side of an imagingapparatus according to one embodiment of the invention, and

FIG. 35 is a perspective view showing the rear side of the imagingapparatus shown in FIG. 34.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described indetail with reference to the drawings. FIG. 1 is a sectional viewillustrating the lens configuration of a zoom lens according to oneembodiment of the invention. The configuration example shown in FIG. 1is the same as the configuration of a zoom lens of Example 1, which willbe described later. In FIG. 1, the left side is the object side and theright side is the image side. An aperture stop St shown in the drawingdoes not necessarily represent the size and the shape thereof, butrepresents the position thereof along the optical axis Z.

As shown in FIG. 1, this zoom lens consists of, in order from the objectside, a first lens group G1 having a positive refractive power, a secondlens group G2 having a negative refractive power, a third lens group G3having a positive refractive power (which corresponds to an mp lensgroup of the invention), and a fourth lens group G4 having a positiverefractive power (which corresponds to a rearmost lens group of theinvention), wherein magnification change is effected by changing all thedistances between the adjacent lens groups.

When this zoom lens is used with an imaging apparatus, it is preferredto provide a cover glass, a prism, and various filters, such as aninfrared cutoff filter and a low-pass filter, etc., between the opticalsystem and an image plane Sim depending on the configuration of thecamera on which the lens is mounted. In the example shown in FIG. 1, anoptical member PP in the form of a plane-parallel plate, which isassumed to represent such elements, is disposed between the lens systemand the image plane Sim.

This zoom lens effects focusing from an object at infinity to a closestobject by moving only the entire third lens group G3 (the mp lens group)along the optical axis. It should be noted that the lens group movedduring focusing may be a part of lens groups forming the third lensgroup G3 (the mp lens group), rather than the entire third lens group G3(the mp lens group). However, effecting focusing by moving only thethird lens group G3 (the mp lens group) allows suppressing variation ofaberrations during focusing. The lens group moved during focusingincludes at least one positive lens and at least one negative lens, andhas a positive refractive power as a whole.

Employing the above-described inner focusing system allows sizereduction and weight reduction of the focusing lens group (the thirdlens group G3) to thereby allow speeding up the autofocus operation. Thefocusing lens group including a positive lens and a negative lens allowssuccessfully suppressing variation of chromatic aberration duringfocusing.

Further, the zoom lens of the invention is configured to satisfy thecondition expressions (1) and (2) below:1.67<f1/fGf<2.70  (1),1.72<f1/fGf<2.60  (1-1),1.15<f1/fGr<1.85  (2),1.20<f1/fGr<1.75  (2-1),where f1 is a focal length of the first lens group, fGf is a focallength of the lens group moved during focusing, and fGr is a focallength of the rearmost lens group.

Satisfying the lower limit of the condition expression (1) allowspreventing the refractive power of the focusing lens group from becomingexcessively weak, and keeping the amount of movement of the focusinglens group during focusing relatively small, which are advantageous forachieving size reduction and weight reduction of the lens system andspeeding up the focusing operation. Alternatively, satisfying the lowerlimit of the condition expression (1) allows preventing the refractivepower of the first lens group G1 from becoming excessively strong, andthis is advantageous for correcting spherical aberration, in particular,at the telephoto side. Satisfying the upper limit of the conditionexpression (1) allows preventing the refractive power of the focusinglens group from becoming excessively strong, and this allows suppressingvariation of aberrations during focusing. Alternatively, satisfying theupper limit of the condition expression (1) allows preventing therefractive power of the first lens group G1 from becoming excessivelyweak, and this allows keeping the entire length of the lens relativelysmall. It should be noted that higher performance can be obtained whenthe condition expression (1-1) is satisfied.

Satisfying the lower limit of the condition expression (2) allowspreventing the refractive power of the fourth lens group G4 (therearmost lens group) from becoming excessively weak and this isadvantageous for size reduction. Alternatively, satisfying the lowerlimit of the condition expression (2) allows preventing the refractivepower of the first lens group G1 from becoming excessively strong, andthis is advantageous for correcting spherical aberration, in particular,at the telephoto side. Satisfying the upper limit of the conditionexpression (2) allows preventing the refractive power of the fourth lensgroup G4 (the rearmost lens group) from becoming excessively strong, andthis allows suppressing coma aberration at the fourth lens group G4 (therearmost lens group). It should be noted that higher performance can beobtained when the condition expression (2-1) is satisfied.

In the zoom lens of this embodiment, it is preferred that the first lensgroup G1 be fixed relative to the image plane Sim during magnificationchange. Fixing the first lens group G1 in this manner allows simplifyingthe frame structure. Comparing to a configuration where the first lensgroup G1 is moved forward toward its telephoto end position, thisconfiguration has advantages such as reducing influence of decenteringof the lenses due to flexure of the lens frame, etc., and facilitatinguse of a dustproof, weather sealed structure.

It is preferred that the fourth lens group G4 (the rearmost lens group)be fixed relative to the image plane Sim during magnification change.Reducing the number of lens groups to be moved in this manner allowsreducing influence of decentering. Also, this configuration allowssuppressing variation of F-number during magnification change, and thisis advantageous for forming a zoom lens having a constant aperture.

It is preferred that the lens group moved during focusing consist of twopositive lenses and one negative lens. This configuration allowssuppressing variation of aberrations during focusing.

It is preferred that the condition expression (3) below be satisfied.Satisfying the lower limit of the condition expression (3) allowspreventing the refractive power of the first lens group G1 from becomingexcessively weak, and this allows keeping the entire length of the lensrelatively small. Satisfying the upper limit of the condition expression(3) is advantageous for correcting spherical aberration, in particular,at the telephoto side. It should be noted that higher performance can beobtained when the condition expression (3-1) is satisfied.1.20<ft/f1<2.20  (3),1.23<ft/f1<2.00  (3-1),where ft is a focal length of the entire system when the lens is focusedon an object at infinity at the telephoto end, and f1 is a focal lengthof the first lens group.

Further, it is preferred that the condition expression (4) below besatisfied. Satisfying the lower limit of the condition expression (4)allows preventing the refractive power of the second lens group G2 frombecoming excessively weak, and this allows keeping the amount ofmovement of the second lens group G2 relatively small. Satisfying theupper limit of the condition expression (4) allows suppressing variationof spherical aberration and astigmatism, in particular, duringmagnification change. It should be noted that higher performance can beobtained when the condition expression (4-1) is satisfied.5.30<ft/|f2|<8.80  (4),5.50<ft/|f2|<8.60  (4-1),where ft is a focal length of the entire system when the lens is focusedon an object at infinity at the telephoto end, and f2 is a focal lengthof the second lens group.

Further, it is preferred that the condition expression (5) below besatisfied. Satisfying the condition expression (5) is advantageous forcorrecting longitudinal chromatic aberration. Also, satisfying thecondition expression (5) allows suppressing variation of chromaticaberration at the wide-angle end and at the telephoto end, and variationof chromatic aberration during focusing. It should be noted that higherperformance can be obtained when the condition expression (5-1), (5-2),or (5-3) is satisfied.57<νdGmp  (5),57<νdGmp<85  (5-1),59<νdGmp  (5-2),59<νdGmp<85  (5-3),where νdGmp is the largest Abbe number of the at least one positive lensin the lens group moved during focusing.

It is preferred that the first lens group G1 consist of, in order fromthe object side, a negative lens, a positive lens, a positive lens, anda positive lens. The first lens group G1 including three positive lensesin this manner allows successfully correcting chromatic aberration andspherical aberration, in particular, at the telephoto side. Further, ina case where the first lens group G1 as a whole has a strong power forthe purpose of size reduction, etc., the above-described configurationallows distributing the power among the lenses, resulting in smalleraberrations at each lens surface.

It is preferred that the second lens group G2 include two positivelenses and two negative lenses. The second lens group G2 having theabove configuration allows smoothly correcting aberrations even when thesecond lens group G2 is provided with a strong power to achieve sizereduction of the front lens element or to reduce the amount of movementof the second lens group G2, and allows successfully correcting comaaberration and chromatic aberration, in particular, at the wide-angleend.

It is preferred that that the zoom lens of the invention consists offour lens groups which consist of, in order from the object side, thefirst lens group G1, the second lens group G2, the mp lens group (thethird lens group G3), and the rearmost lens group (the fourth lens groupG4). Minimizing the number of lens groups and forming the zoom lenshaving the above-described four-group configuration allows simplifyingthe frame structure, and reducing influence of decentering.

It is preferred that the aperture stop St be disposed at the mostobject-side position of the fourth lens group G4 (the rearmost lensgroup). Disposing the aperture stop St at the most object-side positionof the fourth lens group G4 (the rearmost lens group) in place ofbetween lenses of the fourth lens group G4 allows simplifying the framestructure. Further, in the case where the fourth lens group G4 (therearmost lens group) is fixed relative to the image plane Sim duringmagnification change, a constant aperture zoom lens can be formedwithout changing the so-called aperture stop diameter.

In a case where the zoom lens is used in a harsh environment, it ispreferred that the zoom lens be provided with a protective multi-layercoating. Besides the protective coating, the zoom lens may be providedwith an antireflection coating for reducing ghost light, etc., duringuse.

In the example shown in FIG. 1, the optical member PP is disposedbetween the lens system and the image plane Sim. However, in place ofdisposing the various filters, such as a low-pass filter and a filterthat cuts off a specific wavelength range, between the lens system andthe image plane Sim, the various filters may be disposed between thelenses, or coatings having the same functions as the various filters maybe applied to the lens surfaces of some of the lenses.

Next, numerical examples of the zoom lens of the invention aredescribed.

First, a zoom lens of Example 1 is described. FIG. 1 is a sectional viewillustrating the lens configuration of the zoom lens of Example 1. Itshould be noted that, in FIG. 1, and FIGS. 2 to 11 corresponding toExamples 2 to 11, which will be described later, the left side is theobject side and the right side is the image side. The aperture stop Stshown in the drawings does not necessarily represent the size and theshape thereof, but represents the position thereof along the opticalaxis Z. The symbol “Focus” in the drawings denotes a lens group used toeffect focusing, and the symbol “Ois” denotes a lens group used toeffect image stabilization.

The zoom lens of Example 1 has a four-group configuration which consistsof, in order from the object side, a first lens group G1 having apositive refractive power, a second lens group G2 having a negativerefractive power, a third lens group G3 (the mp lens group) having apositive refractive power, and a fourth lens group G4 (the rearmost lensgroup) having a positive refractive power.

Table 1 shows basic lens data of the zoom lens of Example 1, Table 2shows data about specifications of the zoom lens, and Table 3 shows dataabout distances between surfaces to be moved of the zoom lens. In thefollowing description, meanings of symbols used in the tables areexplained with respect to Example 1 as an example. The same explanationsbasically apply to those with respect to Examples 2 to 11.

In the lens data shown in Table 1, each value in the column of “SurfaceNo.” represents a surface number, where the object-side surface of themost object-side element is the 1st surface and the number issequentially increased toward the image side, each value in the columnof “Radius of Curvature” represents the radius of curvature of thecorresponding surface, and each value in the column of “SurfaceDistance” represents the distance along the optical axis Z between thecorresponding surface and the next surface. Each value in the column of“nd” represents the refractive index with respect to the d-line (thewavelength of 587.6 nm) of the corresponding optical element, each valuein the column of “νd” represents the Abbe number with respect to thed-line (the wavelength of 587.6 nm) of the corresponding opticalelement, and each value in the column of “θgF” represents the partialdispersion ratio of the corresponding optical element.

It should be noted that the partial dispersion ratio θgF is expressed bythe formula below:θgF=(ng−nF)/(nF−nC),where ng is a refractive index with respect to the g-line (thewavelength of 435.8 nm), nF is a refractive index with respect to theF-line (the wavelength of 486.1 nm), and nC is a refractive index withrespect to the C-line (the wavelength of 656.3 nm).

The sign with respect to the radius of curvature is provided such that apositive radius of curvature indicates a surface shape that is convextoward the object side, and a negative radius of curvature indicates asurface shape that is convex toward the image side. The basic lens dataalso includes data of the aperture stop St and the optical member PP,and the surface number and the text “(stop)” are shown at the positionin the column of the surface number corresponding to the aperture stopSt. In the lens data shown in Table 1, the value of each surfacedistance that is changed during magnification change is represented bythe symbol “DD[surface number]”. The numerical values corresponding toeach DD[surface number] at the wide-angle end, at the middle position,and at the telephoto end are shown in Table 3.

The data about specifications shown in Table 2 show values of zoommagnification, focal length f′, back focus Bf′, F-number FNo., and totalangle of view 2ω at the wide-angle end, at the middle position, and atthe telephoto end.

With respect to the basic lens data, the data about specifications, andthe data about distances between surfaces to be moved, the unit of angleis degrees, and the unit of length is millimeters; however, any othersuitable units may be used since optical systems are usable when theyare proportionally enlarged or reduced.

TABLE 1 Example 1 - Lens Data Surface Surface No. Radius of CurvatureDistance nd νd θgF  1 274.96102 2.390 1.80100 34.97 0.58642  2 77.901487.850 1.49700 81.54 0.53748  3 −1203.47290 0.200  4 97.12166 5.0001.43875 94.94 0.53433  5 3892.40898 0.200  6 62.76476 6.000 1.4970081.54 0.53748  7 583.05158 DD[7]  8 110.71627 5.710 1.72047 34.710.58350  9 −42.66766 1.550 1.62230 53.17 0.55424 10 24.37958 4.958 11−78.43069 1.260 1.49700 81.54 0.53748 12 25.54612 5.501 1.84661 23.880.62072 13 105.31259 4.001 14 −28.87373 1.250 1.91082 35.25 0.58224 15391.32559 DD[15] 16 −349.16836 2.950 1.80100 34.97 0.58642 17 −38.220340.100 18 63.65733 4.310 1.61800 63.33 0.54414 19 −39.25049 1.150 1.8051825.42 0.61616 20 ∞ DD[20] 21 (stop) ∞ 1.300 22 27.59915 6.985 1.4970081.54 0.53748 23 −58.46986 0.150 24 34.60348 2.550 1.65412 39.68 0.5737825 95.96990 1.610 26 −53.62431 1.210 1.90366 31.31 0.59481 27 22.849616.512 1.49700 81.54 0.53748 28 −84.57206 2.500 29 293.69564 3.7711.80518 25.42 0.61616 30 −23.04083 0.950 1.58913 61.13 0.54067 3133.63593 2.693 32 −43.53615 1.050 1.80100 34.97 0.58642 33 62.251693.752 34 51.53927 6.921 1.80000 29.84 0.60178 35 −39.86271 3.848 3650.27571 7.368 1.48749 70.24 0.53007 37 −26.02866 1.310 1.80518 25.420.61616 38 −69.72800 3.069 39 −30.18711 1.310 1.91082 35.25 0.58224 40−51.30966 26.063  41 ∞ 2.850 1.51633 64.14 0.53531 42 ∞

TABLE 2 Example 1 - Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.6 f′ 51.517 92.224 135.968Bf′ 29.940 29.940 29.940 FNo. 2.88 2.89 2.88 2ω[°] 30.4 17.0 11.6

TABLE 3 Example 1 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.647 24.961 34.686 DD[15] 11.849 7.355 2.477 DD[20]32.001 13.182 8.334

FIG. 12 shows aberration diagrams of the zoom lens of Example 1. Theaberration diagrams shown at the top of FIG. 12 are those of sphericalaberration, offense against the sine condition, astigmatism, distortion,and lateral chromatic aberration at the wide-angle end in this orderfrom the left side, the aberration diagrams shown at the middle of FIG.12 are those of spherical aberration, offense against the sinecondition, astigmatism, distortion, and lateral chromatic aberration atthe middle position in this order from the left side, and the aberrationdiagrams shown at the bottom of FIG. 12 are those of sphericalaberration, offense against the sine condition, astigmatism, distortion,and lateral chromatic aberration at the telephoto end in this order fromthe left side. The aberration diagrams of spherical aberration, offenseagainst the sine condition, astigmatism, and distortion show those withrespect to the d-line (the wavelength of 587.6 nm), which is used as areference wavelength. The aberration diagrams of spherical aberrationshow those with respect to the d-line (the wavelength of 587.6 nm), theC-line (the wavelength of 656.3 nm), the F-line (the wavelength of 486.1nm), and the g-line (the wavelength of 435.8 nm) in the solid line, thelong dashed line, the short dashed line, and the gray line,respectively. The aberration diagrams of astigmatism show those in thesagittal direction and the tangential direction in the solid line andthe short dashed line, respectively. The aberration diagrams of lateralchromatic aberration show those with respect to the C-line (thewavelength of 656.3 nm), the F-line (the wavelength of 486.1 nm), andthe g-line (the wavelength of 435.8 nm) in the long dashed line, theshort dashed line, and the gray line, respectively. It should be notedthat these longitudinal aberration diagrams show aberrations when thelens is focused on an object at infinity. The symbol “FNo.” in theaberration diagrams of spherical aberration and offense against the sinecondition means “F-number”, and the symbol “ω” in the other aberrationdiagrams means “half angle of view”.

FIG. 23 shows lateral aberration diagrams of the zoom lens of Example 1.FIG. 23 shows, in order from the top, lateral aberration diagrams at thewide-angle end, at the middle position, and at the telephoto end. Amongthe lateral aberration diagrams shown in two columns, the lateralaberration diagrams on the left show those with respect to thetangential direction, and the lateral aberration diagrams on the rightshow those with respect to the sagittal direction. Among the lateralaberration diagrams, one at the top shows aberrations at the center ofthe image plane, two at the middle show aberrations at the positionwhere the image height is 80% of the maximum image height on thepositive (+) side, and two at the bottom show aberrations at theposition where the image height is 80% of the maximum image height onthe negative (−) side. It should be noted that, in FIG. 23, aberrationswith respect to the d-line (the wavelength of 587.6 nm), the C-line (thewavelength of 656.3 nm), the F-line (the wavelength of 486.1 nm), andthe g-line (the wavelength of 435.8 nm) are shown in the solid line, thelong dashed line, the short dashed line, and the gray line,respectively. These lateral aberration diagrams show lateral aberrationswhen the lens is focused on an object at infinity. The symbol “ω” in theaberration diagrams means “half angle of view”.

The above-described symbols, meanings and manners of description of thevarious data of Example 1 apply also to the examples described below,unless otherwise noted, and the same explanations are not repeated inthe following description.

Next, a zoom lens of Example 2 is described. The zoom lens of Example 2has a lens group configuration similar to that of the zoom lens ofExample 1. FIG. 2 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 2. Table 4 shows basic lensdata of the zoom lens of Example 2, Table 5 shows data aboutspecifications of the zoom lens, Table 6 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 13 shows aberrationdiagrams of the zoom lens, and FIG. 24 shows lateral aberration diagramsof the zoom lens.

TABLE 4 Example 2 - Lens Data Surface Radius of No. Curvature SurfaceDistance nd νd θgF  1 147.14684 2.312 1.90366 31.31 0.59481  2 71.345796.799 1.49700 81.54 0.53748  3 4466.14983 0.262  4 82.92060 4.5991.45562 91.31 0.53429  5 222.61947 0.209  6 72.46651 7.001 1.48749 70.240.53007  7 2229.87611 DD[7]  8 83.14047 6.305 1.64769 33.79 0.59393  9−54.99973 1.501 1.61772 49.81 0.56035 10 22.65737 6.228 11 −129.467101.009 1.53775 74.70 0.53936 12 23.41440 5.501 1.84661 23.88 0.62072 1390.28797 3.246 14 −32.56444 0.999 1.91082 35.25 0.58224 15 −754.10763DD[15] 16 −139.28102 3.100 1.91082 35.25 0.58224 17 −37.20322 0.100 1845.57357 5.511 1.48749 70.24 0.53007 19 −45.00113 1.100 1.80518 25.420.61616 20 302.73331 DD[20] 21 (stop) ∞ 1.300 22 29.00638 5.564 1.5377574.70 0.53936 23 −83.12098 0.182 24 28.22418 2.499 1.65412 39.68 0.5737825 48.84185 1.900 26 −76.98887 1.210 1.90366 31.31 0.59481 27 20.916137.501 1.53775 74.70 0.53936 28 −71.39743 3.663 29 101.15891 4.7061.80518 25.42 0.61616 30 −24.63022 0.882 1.60300 65.44 0.54022 3126.11599 3.199 32 −41.59530 0.899 1.80100 34.97 0.58642 33 49.709542.255 34 43.72156 5.600 1.80000 29.84 0.60178 35 −36.00246 2.992 3636.16338 5.708 1.48749 70.24 0.53007 37 −25.22381 1.199 1.80518 25.420.61616 38 −148.78795 4.102 39 −27.60609 1.199 1.91082 35.25 0.58224 40−43.25152 23.562  41 ∞ 2.850 1.51633 64.14 0.53531 42 ∞

TABLE 5 Example 2 - Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.6 f′ 51.492 92.178 135.901Bf′ 27.440 27.440 27.440 FNo. 2.89 2.89 2.89 2ω [°] 30.2 17.0 11.6

TABLE 6 Example 2 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.199 24.644 34.908 DD[15] 12.356 7.391 1.751 DD[20]31.802 13.322 8.698

Next, a zoom lens of Example 3 is described. The zoom lens of Example 3has a lens group configuration similar to that of the zoom lens ofExample 1. FIG. 3 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 3. Table 7 shows basic lensdata of the zoom lens of Example 3, Table 8 shows data aboutspecifications of the zoom lens, Table 9 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 14 shows aberrationdiagrams of the zoom lens, and FIG. 25 shows lateral aberration diagramsof the zoom lens.

TABLE 7 Example 3 - Lens Data Surface Radius of No. Curvature SurfaceDistance nd νd θgF  1 263.09263 2.312 1.88100 40.14 0.57010  2 65.868767.199 1.49700 81.54 0.53748  3 −571.64100 0.262  4 65.97392 6.2001.45562 91.31 0.53429  5 1175.27258 0.209  6 81.36467 5.500 1.5377574.70 0.53936  7 614.16494 DD[7]  8 120.18724 5.912 1.72047 34.710.58350  9 −42.77946 1.200 1.62230 53.17 0.55424 10 26.30170 5.468 11−3031.67199 1.009 1.43875 94.94 0.53433 12 24.69032 4.403 1.84661 23.880.62072 13 52.10852 4.001 14 −29.01944 0.999 1.88300 40.76 0.56679 15677.75184 DD[15] 16 −624.58221 3.099 1.91082 35.25 0.58224 17 −48.996090.100 18 84.61141 4.859 1.62041 60.29 0.54266 19 −45.52887 1.100 1.8466623.78 0.62054 20 −11814.82817 DD[20] 21 (stop) ∞ 1.300 22 28.94841 7.0011.49700 81.54 0.53748 23 −70.94964 2.298 24 35.48837 2.499 1.65412 39.680.57378 25 125.19811 1.799 26 −55.44889 1.210 1.90366 31.31 0.59481 2724.47948 7.501 1.49700 81.54 0.53748 28 −71.45146 2.001 29 93.113454.160 1.80518 25.42 0.61616 30 −26.87211 0.849 1.58313 59.37 0.54345 3126.83474 3.501 32 −31.98401 0.901 1.80100 34.97 0.58642 33 64.797042.718 34 52.34160 5.499 1.80000 29.84 0.60178 35 −36.46191 4.001 3656.45949 7.310 1.48749 70.24 0.53007 37 −23.44294 1.199 1.80518 25.420.61616 38 −60.82914 2.999 39 −26.37941 1.199 1.91082 35.25 0.58224 40−35.96318 22.238  41 ∞ 2.850 1.51633 64.14 0.53531 42 ∞

TABLE 8 Example 3 - Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 3.1 f′ 50.359 90.150 157.119Bf′ 26.122 26.122 26.122 FNo. 2.89 2.90 2.92 2ω [°] 31.0 17.2 10.0

TABLE 9 Example 3 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.199 24.327 37.203 DD[15] 16.502 10.829 1.100DD[20] 32.001 14.546 11.399

Next, a zoom lens of Example 4 is described. The zoom lens of Example 4has a lens group configuration similar to that of the zoom lens ofExample 1. FIG. 4 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 4. Table 10 shows basic lensdata of the zoom lens of Example 4, Table 11 shows data aboutspecifications of the zoom lens, Table 12 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 15 shows aberrationdiagrams of the zoom lens, and FIG. 26 shows lateral aberration diagramsof the zoom lens.

TABLE 10 Example 4 - Lens Data Surface Radius of No. Curvature SurfaceDistance nd νd θgF  1 188.13090 2.312 1.80610 33.27 0.58845  2 76.508837.200 1.49700 81.54 0.53748  3 −3204.67292 0.262  4 71.91851 6.2001.43875 94.94 0.53433  5 718.81472 0.209  6 63.83157 5.500 1.43875 94.940.53433  7 286.11890 DD[7]  8 127.11673 5.510 1.72047 34.71 0.58350  9−52.90722 1.200 1.62230 53.17 0.55424 10 24.99227 6.501 11 −273.451101.511 1.59522 67.74 0.54426 12 26.07897 5.501 1.84661 23.88 0.62072 1390.43692 4.000 14 −28.20939 1.001 1.88300 40.76 0.56679 15 −219.42843DD[15] 16 4368.42118 3.099 1.91082 35.25 0.58224 17 −45.70178 0.100 1875.53670 5.511 1.49700 81.54 0.53748 19 −37.32451 1.100 1.80518 25.420.61616 20 −582.89400 DD[20] 21 (stop) ∞ 1.300 22 31.57617 7.001 1.4970081.54 0.53748 23 −84.25408 1.501 24 32.66369 2.500 1.65412 39.68 0.5737825 452.11337 1.799 26 −77.71874 1.210 1.90366 31.31 0.59481 27 23.151155.500 1.49700 81.54 0.53748 28 −93.31207 2.001 29 664.84163 4.1611.80518 25.42 0.61616 30 −28.96139 1.201 1.58313 59.37 0.54345 3123.87736 3.200 32 −37.84433 0.899 1.80100 34.97 0.58642 33 66.370722.215 34 45.41616 8.001 1.80518 25.42 0.61616 35 −36.36637 1.453 3644.07982 7.310 1.48749 70.24 0.53007 37 −23.31946 1.200 1.80518 25.420.61616 38 −147.09849 2.999 39 −27.43891 1.200 1.91082 35.25 0.58224 40−35.75126 22.213  41 ∞ 2.850 1.51633 64.14 0.53531 42 ∞

TABLE 11 Example 4 - Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 3.0 f′ 51.153 91.572 154.995Bf′ 26.096 26.096 26.096 FNo. 2.89 2.89 2.89 2ω [°] 30.6 17.2 10.2

TABLE 12 Example 4 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.199 22.851 34.047 DD[15] 17.079 11.080 1.673DD[20] 28.994 13.341 11.552

Next, a zoom lens of Example 5 is described. The zoom lens of Example 5has a lens group configuration similar to that of the zoom lens ofExample 1. FIG. 5 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 5. Table 13 shows basic lensdata of the zoom lens of Example 5, Table 14 shows data aboutspecifications of the zoom lens, Table 15 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 16 shows aberrationdiagrams of the zoom lens, and FIG. 27 shows lateral aberration diagramsof the zoom lens.

TABLE 13 Example 5 - Lens Data Surface Radius of No. Curvature SurfaceDistance nd νd θgF  1 308.24145 2.390 1.80100 34.97 0.58642  2 78.182667.850 1.49700 81.54 0.53748  3 −340.82791 0.200  4 66.71039 6.6001.43875 94.94 0.53433  5 720.82813 0.200  6 71.57189 4.950 1.49700 81.540.53748  7 271.98720 DD[7]  8 100.51474 5.710 1.72047 34.71 0.58350  9−47.31525 1.550 1.62230 53.17 0.55424 10 25.05895 5.799 11 −81.149051.260 1.49700 81.54 0.53748 12 26.42066 5.385 1.84661 23.88 0.62072 13110.30764 3.945 14 −30.83422 1.250 1.91082 35.25 0.58224 15 339.66055DD[15] 16 −578.30556 2.950 1.80100 34.97 0.58642 17 −44.53935 0.100 1876.28815 4.310 1.61800 63.33 0.54414 19 −43.38154 1.150 1.80518 25.420.61616 20 ∞ DD[20] 21 (stop) ∞ 1.300 22 27.81766 6.849 1.49700 81.540.53748 23 −58.16078 0.150 24 34.51417 2.550 1.65412 39.68 0.57378 25107.98255 1.610 26 −54.74993 1.210 1.90366 31.31 0.59481 27 23.445075.499 1.49700 81.54 0.53748 28 −83.55949 2.500 29 343.99918 3.7711.80518 25.42 0.61616 30 −24.56535 0.950 1.58913 61.13 0.54067 3139.79185 2.559 32 −45.16452 1.050 1.80100 34.97 0.58642 33 60.119394.533 34 51.91667 6.541 1.80000 29.84 0.60178 35 −39.70261 4.000 3654.95096 6.950 1.48749 70.24 0.53007 37 −27.73386 1.310 1.80518 25.420.61616 38 −89.67633 3.413 39 −27.15780 1.310 1.91082 35.25 0.58224 40−45.53256 24.577  41 ∞ 2.850 1.51633 64.14 0.53531 42 ∞

TABLE 14 Example 5 - Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.4 f′ 51.515 92.219 125.696Bf′ 28.455 28.455 28.455 FNo. 2.88 2.89 2.89 2ω [°] 30.4 17.0 12.4

TABLE 15 Example 5 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.199 22.040 29.321 DD[15] 14.144 8.593 3.929 DD[20]27.855 12.565 9.948

Next, a zoom lens of Example 6 is described. The zoom lens of Example 6has a lens group configuration similar to that of the zoom lens ofExample 1. FIG. 6 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 6. Table 16 shows basic lensdata of the zoom lens of Example 6, Table 17 shows data aboutspecifications of the zoom lens, Table 18 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 17 shows aberrationdiagrams of the zoom lens, and FIG. 28 shows lateral aberration diagramsof the zoom lens.

TABLE 16 Example 6 - Lens Data Surface Radius of No. Curvature SurfaceDistance nd νd θgF  1 379.59503 2.390 1.80100 34.97 0.58642  2 87.063437.850 1.49700 81.54 0.53748  3 −423.40525 0.200  4 77.08956 6.6001.43875 94.94 0.53433  5 505.15031 0.200  6 74.14509 4.950 1.49700 81.540.53748  7 428.65265 DD[7]  8 95.00168 5.710 1.72047 34.71 0.58350  9−42.18184 1.550 1.62230 53.17 0.55424 10 25.82252 4.852 11 −127.507721.260 1.49700 81.54 0.53748 12 27.56506 4.000 1.84661 23.88 0.62072 13102.12490 3.395 14 −31.04306 1.250 1.91082 35.25 0.58224 15 593.08219DD[15] 16 −587.37289 2.950 1.80100 34.97 0.58642 17 −43.88242 0.100 1878.12881 4.310 1.61800 63.33 0.54414 19 −42.34007 1.150 1.80518 25.420.61616 20 ∞ DD[20] 21 (stop) ∞ 1.300 22 27.72433 6.373 1.49700 81.540.53748 23 −59.65321 0.150 24 34.01198 2.550 1.65412 39.68 0.57378 2593.88248 1.610 26 −54.41210 1.210 1.90366 31.31 0.59481 27 23.355435.569 1.49700 81.54 0.53748 28 −77.98799 2.500 29 394.61491 3.7711.80518 25.42 0.61616 30 −24.49939 0.950 1.58913 61.13 0.54067 3137.65964 2.511 32 −48.39346 1.050 1.80100 34.97 0.58642 33 60.298124.948 34 52.39389 5.299 1.80000 29.84 0.60178 35 −39.28541 3.134 3653.75550 7.501 1.48749 70.24 0.53007 37 −26.62926 1.310 1.80518 25.420.61616 38 −98.73317 6.921 39 −26.89205 1.310 1.91082 35.25 0.58224 40−46.99846 18.856  41 ∞ 2.850 1.51633 64.14 0.53531 42 ∞

TABLE 17 Example 6 - Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.4 f′ 51.515 92.219 125.696Bf′ 22.736 22.736 22.736 FNo. 2.88 2.89 2.88 2ω [°] 30.4 17.0 12.4

TABLE 18 Example 6 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.199 26.087 34.640 DD[15] 13.697 7.573 2.495 DD[20]32.001 13.236 9.762

Next, a zoom lens of Example 7 is described. The zoom lens of Example 7has a lens group configuration similar to that of the zoom lens ofExample 1. FIG. 7 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 7. Table 19 shows basic lensdata of the zoom lens of Example 7, Table 20 shows data aboutspecifications of the zoom lens, Table 21 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 18 shows aberrationdiagrams of the zoom lens, and FIG. 29 shows lateral aberration diagramsof the zoom lens.

TABLE 19 Example 7 - Lens Data Surface Surface No. Radius of CurvatureDistance nd νd θgF 1 358.57195 2.320 1.80100 34.97 0.58642 2 85.097807.200 1.49700 81.54 0.53748 3 −386.19076 0.200 4 72.25745 6.972 1.4387594.94 0.53433 5 ∞ 0.200 6 69.93587 5.200 1.49700 81.54 0.53748 7235.70554 DD[7]  8 96.21157 6.291 1.72047 34.71 0.58350 9 −43.594891.530 1.62230 53.17 0.55424 10 24.59706 5.600 11 −73.29120 1.410 1.4970081.54 0.53748 12 27.09637 4.000 1.84661 23.88 0.62072 13 123.98633 2.79914 −30.96977 1.200 1.91082 35.25 0.58224 15 353.74684 DD[15] 16−406.80952 2.850 1.80100 34.97 0.58642 17 −43.60631 0.100 18 74.864024.260 1.61800 63.33 0.54414 19 −43.68363 1.170 1.80518 25.42 0.61616 20∞ DD[20] 21 (stop) ∞ 1.300 22 28.04424 7.050 1.49700 81.54 0.53748 23−59.60296 0.150 24 34.77250 2.570 1.65412 39.68 0.57378 25 89.214371.800 26 −51.39895 1.110 1.90366 31.31 0.59481 27 24.25217 5.266 1.4970081.54 0.53748 28 −60.88125 2.800 29 733.80887 3.771 1.80518 25.420.61616 30 −23.29690 0.950 1.58913 61.13 0.54067 31 39.10301 2.801 32−39.71546 1.000 1.80100 34.97 0.58642 33 62.34880 4.199 34 54.236065.285 1.80000 29.84 0.60178 35 −37.12789 4.367 36 51.75623 6.461 1.4874970.24 0.53007 37 −25.77385 1.310 1.80518 25.42 0.61616 38 −86.833964.400 39 −27.43970 1.260 1.91082 35.25 0.58224 40 −40.98080 25.514  41 ∞2.850 1.51633 64.14 0.53531 42 ∞

TABLE 20 Example 7- Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.6 f′ 51.516 92.222 135.965Bf′ 29.393 29.393 29.393 FNo. 2.88 2.89 2.88 2ω[°] 30.6 17.0 11.6

TABLE 21 Example 7 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.191 22.931 32.107 DD[15] 14.409 8.821 2.687 DD[20]29.090 12.939 9.896

Next, a zoom lens of Example 8 is described. The zoom lens of Example 8has a five-group configuration which consists of, in order from theobject side, a first lens group G1 having a positive refractive power, asecond lens group G2 having a negative refractive power, a third lensgroup G3 having a negative refractive power, a fourth lens group G4 (themp lens group) having a positive refractive power, and a fifth lensgroup G5 (the rearmost lens group) having a positive refractive power.FIG. 8 is a sectional view illustrating the lens configuration of thezoom lens of Example 8. Table 22 shows basic lens data of the zoom lensof Example 8, Table 23 shows data about specifications of the zoom lens,Table 24 shows data about distances between surfaces to be moved of thezoom lens, FIG. 19 shows aberration diagrams of the zoom lens, and FIG.30 shows lateral aberration diagrams of the zoom lens.

TABLE 22 Example 8 - Lens Data Surface Surface No. Radius of CurvatureDistance nd νd θgF 1 303.47850 2.390 1.80100 34.97 0.58642 2 75.717597.850 1.49700 81.54 0.53748 3 −338.62836 0.200 4 67.27723 6.600 1.4387594.94 0.53433 5 706.55071 0.200 6 67.16666 4.950 1.49700 81.54 0.53748 7287.46150 DD[7]  8 98.18370 5.710 1.72047 34.71 0.58350 9 −49.054011.550 1.62230 53.17 0.55424 10 24.62771 DD[10] 11 −75.51985 1.2601.49700 81.54 0.53748 12 25.58057 5.388 1.84661 23.88 0.62072 13106.72525 3.704 14 −31.24101 1.250 1.91082 35.25 0.58224 15 268.03486DD[15] 16 −521.95122 2.950 1.80100 34.97 0.58642 17 −44.70833 0.100 1873.37158 4.310 1.61800 63.33 0.54414 19 −43.22381 1.150 1.80518 25.420.61616 20 ∞ DD[20] 21 (stop) ∞ 1.300 22 27.81729 6.868 1.49700 81.540.53748 23 −57.84476 0.150 24 34.09999 2.550 1.65412 39.68 0.57378 25102.68991 1.610 26 −54.83237 1.210 1.90366 31.31 0.59481 27 23.141515.662 1.49700 81.54 0.53748 28 −87.93105 2.500 29 372.91281 3.7711.80518 25.42 0.61616 30 −24.31863 0.950 1.58913 61.13 0.54067 3136.29877 3.256 32 −44.08151 1.050 1.80100 34.97 0.58642 33 60.805193.831 34 50.53032 5.748 1.80000 29.84 0.60178 35 −39.43779 4.000 3648.86127 8.012 1.48749 70.24 0.53007 37 −26.40743 1.310 1.80518 25.420.61616 38 −86.68447 3.157 39 −27.70770 1.310 1.91082 35.25 0.58224 40−44.10429 24.901  41 ∞ 2.850 1.51633 64.14 0.53531 42 ∞

TABLE 23 Example 8- Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.6 f′ 51.514 92.218 135.960Bf′ 28.781 28.781 28.781 FNo. 2.88 2.89 2.88 2ω[°] 30.4 17.0 11.6

TABLE 24 Example 8 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.199 20.933 29.242 DD[10] 6.235 6.638 6.783 DD[15]14.153 8.593 2.488 DD[20] 26.710 12.132 9.785

Next, a zoom lens of Example 9 is described. The zoom lens of Example 9has a lens group configuration similar to that of the zoom lens ofExample 8. FIG. 9 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 9. Table 25 shows basic lensdata of the zoom lens of Example 9, Table 26 shows data aboutspecifications of the zoom lens, Table 27 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 20 shows aberrationdiagrams of the zoom lens, and FIG. 31 shows lateral aberration diagramsof the zoom lens.

TABLE 25 Example 9 - Lens Data Surface Surface No. Radius of CurvatureDistance nd νd θgF 1 257.91881 2.390 1.83400 37.16 0.57759 2 73.186127.850 1.49700 81.54 0.53748 3 −329.42308 0.200 4 62.30117 6.600 1.4370095.10 0.53364 5 849.43043 0.200 6 72.87230 4.950 1.49700 81.54 0.53748 7263.78540 DD[7]  8 107.78333 5.710 1.72047 34.71 0.58350 9 −47.768211.550 1.62230 53.17 0.55424 10 25.18309 5.631 11 −93.23488 1.260 1.4970081.54 0.53748 12 26.34063 3.999 1.84661 23.88 0.62072 13 99.67576 DD[13]14 −31.09640 1.250 1.91082 35.25 0.58224 15 318.83279 DD[15] 16−974.57258 2.950 1.80100 34.97 0.58642 17 −43.76266 0.100 18 65.142694.310 1.53775 74.70 0.53936 19 −49.97731 1.150 1.80518 25.42 0.61616 20∞ DD[20] 21 (stop) ∞ 1.300 22 28.69392 7.001 1.49700 81.54 0.53748 23−59.87797 0.150 24 34.09590 2.550 1.65412 39.68 0.57378 25 85.639481.610 26 −54.93056 1.210 1.90366 31.31 0.59481 27 24.95033 6.359 1.4970081.54 0.53748 28 −76.31225 2.500 29 141.63653 3.771 1.80518 25.420.61616 30 −23.83965 0.950 1.58913 61.13 0.54067 31 30.73799 2.499 32−37.50492 1.050 1.80100 34.97 0.58642 33 53.05759 2.617 34 55.654536.802 1.83400 37.16 0.57759 35 −41.09507 4.001 36 52.54294 6.611 1.4874970.24 0.53007 37 −38.16059 1.310 1.80518 25.42 0.61616 38 −57.002363.270 39 −28.19030 1.310 1.91082 35.25 0.58224 40 −47.93144 28.451  41 ∞2.850 1.51633 64.14 0.53531 42 ∞

TABLE 26 Example 9- Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.6 f′ 51.526 92.240 135.992Bf′ 32.332 32.332 32.332 FNo. 2.88 2.89 2.88 2ω[°] 30.4 17.0 11.6

TABLE 27 Example 9 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.199 21.287 29.769 DD[13] 4.000 4.585 4.348 DD[15]14.542 8.794 2.472 DD[20] 26.846 11.921 9.998

Next, a zoom lens of Example 10 is described. The zoom lens of Example10 has a lens group configuration similar to that of the zoom lens ofExample 1. FIG. 10 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 10. Table 28 shows basic lensdata of the zoom lens of Example 10, Table 29 shows data aboutspecifications of the zoom lens, Table 30 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 21 shows aberrationdiagrams of the zoom lens, and FIG. 32 shows lateral aberration diagramsof the zoom lens.

TABLE 28 Example 10 - Lens Data Surface Surface No. Radius of CurvatureDistance nd νd θgF 1 206.18300 2.390 1.80100 34.97 0.58642 2 77.370337.850 1.43875 94.94 0.53433 3 −468.12933 0.200 4 68.18946 6.600 1.4387594.94 0.53433 5 665.76128 0.200 6 75.70042 4.950 1.49700 81.54 0.53748 7318.83987 DD[7]  8 97.24407 5.710 1.72047 34.71 0.58350 9 −43.726451.550 1.62230 53.17 0.55424 10 24.36854 5.706 11 −73.08228 1.260 1.4970081.54 0.53748 12 25.31089 4.204 1.84661 23.88 0.62072 13 107.97061 2.79914 −30.56048 1.250 1.91082 35.25 0.58224 15 253.08206 DD[15] 16−16125.23228 2.950 1.80100 34.97 0.58642 17 −40.12049 0.100 18 80.783594.310 1.59282 68.62 0.54414 19 −40.99835 1.150 1.84666 23.78 0.62054 20−145.20798 7.757 21 −92.18977 1.500 1.80000 29.84 0.60178 22 −254.53436DD[22] 23 (stop) ∞ 1.300 24 27.68095 7.001 1.49700 81.54 0.53748 25−56.35341 0.150 26 32.42093 2.550 1.65412 39.68 0.57378 27 119.288471.610 28 −55.80214 1.210 1.90366 31.31 0.59481 29 23.16845 6.126 1.4970081.54 0.53748 30 −90.54469 2.500 31 590.71987 3.771 1.80518 25.420.61616 32 −24.23391 0.950 1.58913 61.13 0.54067 33 37.50164 3.358 34−43.90672 1.050 1.80100 34.97 0.58642 35 57.93149 4.715 36 51.334595.893 1.80000 29.84 0.60178 37 −38.45068 1.953 38 50.11025 7.136 1.4874970.24 0.53007 39 −28.43175 1.310 1.80518 25.42 0.61616 40 −83.918574.329 41 −26.99010 1.310 1.91082 35.25 0.58224 42 −47.11637 24.016  43 ∞2.850 1.51633 64.14 0.53531 44 ∞

TABLE 29 Example 10- Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.6 f′ 51.519 92.228 135.974Bf′ 27.894 27.894 27.894 FNo. 2.87 2.87 2.88 2ω[°] 30.4 17.0 11.6

TABLE 30 Example 10 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.279 23.274 32.917 DD[15] 11.721 7.221 2.117 DD[22]23.835 6.340 1.801

Next, a zoom lens of Example 11 is described. The zoom lens of Example11 has a lens group configuration similar to that of the zoom lens ofExample 1. FIG. 11 is a sectional view illustrating the lensconfiguration of the zoom lens of Example 11. Table 31 shows basic lensdata of the zoom lens of Example 11, Table 32 shows data aboutspecifications of the zoom lens, Table 33 shows data about distancesbetween surfaces to be moved of the zoom lens, FIG. 22 shows aberrationdiagrams of the zoom lens, and FIG. 33 shows lateral aberration diagramsof the zoom lens.

TABLE 31 Example 11 - Lens Data Surface Surface No. Radius of CurvatureDistance nd νd θgF 1 180.37474 2.390 1.80100 34.97 0.58642 2 69.148687.850 1.49700 81.54 0.53748 3 −481.66507 0.200 4 60.15068 7.500 1.4387594.94 0.53433 5 1142.76498 0.200 6 76.86117 4.500 1.49700 81.54 0.537487 187.53228 DD[7]  8 111.60159 5.710 1.72047 34.71 0.58350 9 −39.893811.550 1.62230 53.17 0.55424 10 24.07077 4.980 11 −64.75230 1.260 1.4970081.54 0.53748 12 24.25512 5.408 1.84661 23.88 0.62072 13 94.37171 2.79914 −28.39083 1.250 1.91082 35.25 0.58224 15 193.35819 DD[15] 16−2763.02905 2.950 1.80100 34.97 0.58642 17 −42.42344 0.100 18 118.965644.310 1.59282 68.62 0.54414 19 −37.94715 1.150 1.84666 23.78 0.62054 20−229.69252 7.412 21 389.16162 2.200 1.68893 31.07 0.60041 22 −215.34129DD[22] 23 (stop) ∞ 1.300 24 27.53581 7.001 1.49700 81.54 0.53748 25−57.95147 0.150 26 36.50795 2.550 1.65412 39.68 0.57378 27 105.691641.610 28 −54.28866 1.210 1.90366 31.31 0.59481 29 22.84035 6.968 1.4970081.54 0.53748 30 −80.66013 2.500 31 381.31349 3.771 1.80518 25.420.61616 32 −25.25989 0.950 1.58913 61.13 0.54067 33 39.74943 3.501 34−39.07424 1.050 1.80100 34.97 0.58642 35 67.59646 4.073 36 53.404165.837 1.80000 29.84 0.60178 37 −38.04851 4.001 38 47.49724 6.893 1.4874970.24 0.53007 39 −27.13146 1.310 1.80518 25.42 0.61616 40 −85.375973.001 41 −29.19153 1.310 1.91082 35.25 0.58224 42 −47.66122 25.665  43 ∞2.850 1.51633 64.14 0.53531 44 ∞

TABLE 32 Example 11- Specification (d-line) Wide Angle End MiddleTelephoto End Zoom Magnification 1.0 1.8 2.6 f′ 51.511 92.212 135.951Bf′ 29.545 29.545 29.545 FNo. 2.88 2.89 2.88 2ω[°] 30.6 17.0 11.6

TABLE 33 Example 11 - Distances Relating to Zoom Wide Angle End MiddleTelephoto End DD[7] 1.697 21.960 30.401 DD[15] 10.593 6.211 1.452 DD[22]21.360 5.480 1.796

Table 34 shows values corresponding to the condition expressions (1) to(5) of the zoom lenses of Examples 1 to 11. In all the examples, thed-line is used as a reference wavelength, and the values shown in Table34 below are with respect to the reference wavelength.

TABLE 34 Condition No. Expression Example 1 Example 2 Example 3 Example4 Example 5 Example 6 (1) f1/fGf 2.214 1.996 1.870 1.844 1.842 2.043 (2)f1/fGr 1.375 1.631 1.393 1.272 1.384 1.530 (3) ft/f1 1.477 1.380 1.6781.722 1.413 1.277 (4) ft/|f2| 7.637 6.780 7.857 7.041 6.628 5.890 (5)νdGmp 63.33 70.23 60.29 63.33 63.33 63.33 Condition No. ExpressionExample 7 Example 8 Example 9 Example 10 Example 11 (1) f1/fGf 1.8801.787 1.799 2.470 1.770 (2) f1/fGr 1.394 1.339 1.326 1.548 1.282 (3)ft/f1 1.498 1.583 1.572 1.477 1.592 (4) ft/|f2| 7.009 7.342 7.204 7.3318.313 (5) νdGmp 63.33 63.33 67.73 68.62 68.62

As can be seen from the above-described data, each of the zoom lenses ofExamples 1 to 11 satisfies the condition expressions (1) to (5), and isa telephoto zoom lens having an angle of view of about 10 to 13 degreesat the telephoto end, a zoom ratio of about 2.4 to 3.1, a high apertureratio with a maximum aperture of about F2.8 across the entire zoomrange, and having high optical performance, wherein the focusing lensgroup is compact and light weight, and the amount of movement of thefocusing lens group is small.

Next, one embodiment of an imaging apparatus according to the inventionis described with reference to FIGS. 34 and 35. FIGS. 34 and 35 areperspective views showing the front side and the rear side,respectively, of a camera 30. The camera 30 is a non-reflex digitalcamera, to which a replaceable lens 20 formed by a zoom lens 1 accordingto the embodiment of the invention housed in a lens barrel is removablymounted.

The camera 30 includes a camera body 31, and a shutter button 32 and apower button 33 are disposed on the top side of the camera body 31. Onthe rear side of the camera body 31, operation sections 34 and 35, and adisplay section 36 are disposed. The display section 36 displays a takenimage, and an image within the angle of view before an imaging operationis performed.

At the center of the front side of the camera body 31, an imagingaperture, through which light from the subject enters, is formed, and amount 37 is disposed at the position corresponding to the imagingaperture. The replaceable lens 20 is mounted on the camera body 31 viathe mount 37.

In the camera body 31, an image sensor (not shown), such as a CCD, forreceiving an image of the subject formed by the replaceable lens 20 andoutputting an image signal according to the image of the subject, asignal processing circuit for processing the image signal outputted fromthe image sensor to generate an image, a recording medium for recordingthe generated image, etc., are disposed. With this camera 30, a stillimage or a moving image can be taken when the shutter button 32 ispressed, and the image data obtained by the imaging operation isrecorded in the recording medium.

The camera 30 of this embodiment, which is provided with the zoom lens 1of the invention, is compact and light weight, and allows obtaining highquality images.

The present invention has been described with reference to theembodiments and the examples. However, the invention is not limited tothe above-described embodiments and examples, and various modificationsmay be made to the invention. For example, the values of the radius ofcurvature, the surface distance, the refractive index, the Abbe number,the aspheric coefficients, etc., of each lens are not limited to thevalues shown in the above-described examples and may take differentvalues.

While the embodiment of the imaging apparatus is described and shown inthe drawings as a non-reflex (so-called mirrorless) digital camera as anexample, this is not intended to limit the imaging apparatus of theinvention. For example, the invention is also applicable to imagingapparatuses, such as video cameras, digital cameras, motion picturecameras, and broadcasting cameras.

What is claimed is:
 1. A zoom lens consisting of four or five lensgroups as a whole, which consist of, in order from an object side, afirst lens group having a positive refractive power, a second lens grouphaving a negative refractive power, one or two middle lens groupsincluding a mp lens group having a positive refractive power, and arearmost lens group disposed at the most image side position of theentire system and having a positive refractive power, whereinmagnification change is effected by changing all distances between theadjacent lens groups, focusing from an object at infinity to a closestobject is effected by moving only the entire mp lens group or only apart of lens groups forming the mp lens group along an optical axis, thelens group moved during focusing includes at least one positive lens andat least one negative lens and has a positive refractive power as awhole, and the condition expressions (1) and (2) below are satisfied:1.67<f1/fGf<2.70  (1), and1.15<f1/fGr<1.85  (2), where f1 is a focal length of the first lensgroup, fGf is a focal length of the lens group moved during focusing,and fGr is a focal length of the rearmost lens group.
 2. The zoom lensas claimed in claim 1, wherein the first lens group is fixed relative toan image plane during magnification change.
 3. The zoom lens as claimedin claim 1, wherein the rearmost lens group is fixed relative to animage plane during magnification change.
 4. The zoom lens as claimed inclaim 1, wherein the lens group moved during focusing consists of twopositive lenses and one negative lens.
 5. The zoom lens as claimed inclaim 1, wherein focusing from an object at infinity to a closest objectis effected by moving only the entire mp lens group along the opticalaxis.
 6. The zoom lens as claimed in claim 1, wherein the conditionexpression (3) below is satisfied:1.20<ft/f1<2.20  (3), where ft is a focal length of the entire systemwhen the lens is focused on an object at infinity at a telephoto end. 7.The zoom lens as claimed in claim 1, wherein the condition expression(4) below is satisfied:5.30<ft/|f2|<8.80  (4), where ft is a focal length of the entire systemwhen the lens is focused on an object at infinity at a telephoto end,and f2 is a focal length of the second lens group.
 8. The zoom lens asclaimed in claim 1, wherein the condition expression (5) below issatisfied:57<νdGmp  (5), where νdGmp is the largest Abbe number of the at leastone positive lens in the lens group moved during focusing.
 9. The zoomlens as claimed in claim 1, wherein the first lens group consists of, inorder from the object side, a negative lens, a positive lens, a positivelens, and a positive lens.
 10. The zoom lens as claimed in claim 1,wherein the second lens group includes two positive lenses and twonegative lenses.
 11. The zoom lens as claimed in claim 1, consisting offour lens groups which consist of, in order from the object side, thefirst lens group, the second lens group, the mp lens group, and therearmost lens group.
 12. The zoom lens as claimed in claim 1, wherein astop is disposed at the most object-side position of the rearmost lensgroup.
 13. The zoom lens as claimed in claim 1, wherein the conditionexpression (1-1) below is satisfied:1.72<f1/fGf<2.60  (1-1).
 14. The zoom lens as claimed in claim 1,wherein the condition expression (2-1) below is satisfied:1.20<f1/fGr<1.75  (2-1).
 15. The zoom lens as claimed in claim 1,wherein the condition expression (3-1) below is satisfied:1.23<ft/f1<2.00  (3-1), where ft is a focal length of the entire systemwhen the lens is focused on an object at infinity at a telephoto end.16. The zoom lens as claimed in claim 1, wherein the conditionexpression (4-1) below is satisfied:5.50<ft/|f2|<8.60  (4-1), where ft is a focal length of the entiresystem when the lens is focused on an object at infinity at a telephotoend, and f2 is a focal length of the second lens group.
 17. The zoomlens as claimed in claim 1, wherein the condition expression (5-1) belowis satisfied:57<νdGmp<85  (5-1), where νdGmp is the largest Abbe number of the atleast one positive lens in the lens group moved during focusing.
 18. Thezoom lens as claimed in claim 1, wherein the condition expression (5-2)below is satisfied:59<νdGmp  (5-2), where νdGmp is the largest Abbe number of the at leastone positive lens in the lens group moved during focusing.
 19. The zoomlens as claimed in claim 1, wherein the condition expression (5-3) belowis satisfied:59<νdGmp<85  (5-3), where νdGmp is the largest Abbe number of the atleast one positive lens in the lens group moved during focusing.
 20. Animaging apparatus comprising the zoom lens as claimed in claim 1.